JP2000155096A - Moisture detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reliably detect the sticking of moisture even when a drop of moisture is stuck and to detect the concentration of the solute in the moisture reliably and accurately regardless of the size of the stuck quantity of moisture. SOLUTION: This moisture detecting device is provided with an electroluminescence (EL) 9 as a diffused light generation section, a prism 7 having a detecting face 15 on which part of the diffused light is totally reflected, and a detection section 10 receiving the totally reflected light from the detecting face 15 of the prism 7 and detecting the positional drift of the light intensity distribution due to the sticking of moisture to the detecting face 15. The detection section 10 is provided with an optical system 11 arranged to form an image at an infinite point and a position detector 12, and the concentration of the solute in the moisture stuck to the detecting face 15 can be judged in response to the positional drift quantity detected by the position detector 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for determining whether or not moisture has adhered to a detection surface, and for determining the concentration of a substance such as salt contained in the moisture which has adhered to the detection surface (hereinafter referred to as "concentration of solute in moisture"). The present invention relates to a moisture detecting device used for determining the water content. In particular, the present invention relates to a moisture detecting device suitable for detecting the concentration of a solute in moisture accumulated on a road surface.

[0002]

2. Description of the Related Art In particular, in cold regions, antifreezing agents such as sodium chloride and calcium chloride are sprayed on snowy road surfaces or frozen road surfaces in order to ensure safe running of vehicles. This type of deicing agent needs to minimize the amount of application to the road surface in order to adversely affect nearby trees and cause rust on vehicles running on the road surface. In recent years, various moisture detection devices that measure the concentration of solutes in the moisture accumulated on the road surface have been proposed, in order to minimize the amount of spray of the antifreeze,
When the detection value of the concentration by the moisture detecting device becomes equal to or less than a predetermined value at which the antifreezing effect and the thawing effect are obtained, the antifreezing agent is sprayed.

FIG. 37 shows the structure and principle of a conventional moisture detecting apparatus 101. The illustrated moisture detecting device 101 has a pair of electrodes 102, 102 buried in a road. Since each electrode 102 is exposed on the road surface R, when moisture w accumulates on the road surface R, conduction between the electrodes 102 and 102 is established. In this moisture detection device, the resistance value between the electrodes 102, 102 is measured by a resistance value measuring device 103, and thereby the conductivity of the moisture w accumulated on the road surface R is obtained. Since the conductivity of the water w is proportional to the ion concentration in the water, if the antifreeze to be sprayed is specified, the concentration of the antifreeze in the water can be obtained from the value measured by the resistance value measuring device 103.

[0004]

In order to obtain a reliable and accurate measurement result with this type of moisture detecting device, first, as shown in FIG. So that it is fully energized,
The water level h on the road surface R needs to be an appropriate value. In the drawings, the arrows indicate the flow of current.

Therefore, even if moisture w exists on the road surface R,
As shown in FIG. 38, if the space between the electrodes 102 and 102 is not completely filled with the moisture w, the conduction between the electrodes 102 and 102 does not occur, and the concentration of the solute in the moisture w cannot be detected. Also, even if the space between the electrodes 102, 102 is completely filled with the moisture w, as shown in FIG. 39, if the water level h of the moisture w on the road surface R is not sufficient, the current flow changes, and FIG. The current does not flow as in the case shown in (1). For this reason, the conductivity of the water w becomes small, and the detected value of the concentration becomes small. Furthermore, as shown in FIG. 40, in a state where moisture w is attached such that only partial conduction between the electrodes 102 and 102 occurs,
The detected value of the concentration of the solute in the water w is smaller.

The present invention has been made in view of the above-mentioned problem. In order to determine whether or not moisture has adhered to a predetermined detection surface, even if only one droplet of moisture has adhered, it is ensured that the moisture adheres. An object of the present invention is to provide a moisture detection device that can detect the moisture. Another object of the present invention is to
It is an object of the present invention to provide a moisture detection device capable of reliably and accurately detecting the concentration of a solute in water for determining the concentration of the solute in the water attached to the detection surface, regardless of the amount of the attached water. .

[0007]

According to a first aspect of the present invention, there is provided a moisture detecting apparatus comprising: a diffused light generator; and a detection surface on which a part of the diffused light from the diffused light generator is totally reflected. A light-transmitting member that causes a difference in critical angle depending on whether moisture is attached to the detection surface, and a light intensity distribution due to the attachment of moisture to the detection surface by receiving total reflection light on the detection surface of the light-transmitting member. And a determination unit that determines the adhesion of moisture to the detection surface based on the detection of the displacement by the detection unit.

[0008] According to a second aspect of the present invention, there is provided a moisture detecting apparatus.
A diffused light generating section, and a detecting surface on which a part of the diffused light from the diffused light generating section is totally reflected, and a light transmission that causes a difference in a critical angle depending on a concentration of a solute in moisture attached to the detecting surface. A member, a detection unit that receives total reflection light from the detection surface of the light transmitting member and detects a position shift of a light intensity distribution due to adhesion of moisture to the detection surface, and a position shift detected by the detection unit. A determination unit for determining the concentration of the solute in the moisture attached to the detection surface according to the amount of the solute.

[0009] According to a third aspect of the present invention, there is provided a moisture detecting apparatus.
3. The moisture detection device according to claim 1, wherein the detection unit includes an optical system arranged to form an image at infinity and a position detector.

[0010] According to a fourth aspect of the present invention, there is provided a moisture detector.
The moisture detecting device according to any one of claims 1 to 3, wherein the light transmitting member is provided with a temperature detecting means for detecting a temperature.

[0011] According to a fifth aspect of the present invention, there is provided a moisture detecting apparatus.
5. The moisture detecting device according to claim 1, wherein the light transmitting member has a surface parallel to the detection surface. 6.

[0012] According to a sixth aspect of the present invention, there is provided a moisture detecting apparatus comprising:
The moisture detection device according to any one of claims 1 to 5, wherein a detection surface of the light transmitting member is covered with a water-permeable protective plate.

According to a seventh aspect of the present invention, there is provided a moisture detecting apparatus comprising:
The moisture detection device according to any one of claims 1 to 5, wherein a detection surface of the light transmitting member is covered with a protection plate having a plurality of moisture introduction holes for introducing moisture onto the detection surface. The protection plate is provided close to the detection surface so as to diffuse moisture on the detection surface.

[0014] The moisture detecting device according to the invention of claim 8 is:
8. The moisture detection device according to claim 6, wherein the protection plate is heated by a heating element. 9.

According to a ninth aspect of the present invention, there is provided a moisture detecting device comprising:
The moisture detecting device according to claim 1, wherein a diffusion member that diffuses moisture on the detection surface is provided at a position near the detection surface of the light transmitting member.

A moisture detector according to a tenth aspect of the present invention is the moisture detector according to any one of the first to fifth aspects, wherein a position close to the detection surface of the light-transmitting member is close to the detection surface. A diffusion member for diffusing the attached moisture is provided, and the diffusion member is provided with a plurality of moisture introduction holes for introducing moisture onto the detection surface.

According to an eleventh aspect of the present invention, in the moisture detecting apparatus according to any one of the first to tenth aspects, the detecting surface of the light transmitting member drains the moisture on the detecting surface. For drainage.

A moisture detector according to a twelfth aspect of the present invention is the moisture detector according to any one of the first to eleventh aspects, wherein the diffused light generator, the light transmitting member, and the detector are provided in a double form. It is accommodated and arranged inside an inner case of a housing case having a structure, and the inner case is formed detachably with respect to the outer case.

According to a thirteenth aspect of the present invention, there is provided the moisture detecting device according to any one of the first to twelfth aspects, wherein specularly reflected light from a detection surface around the light transmitting member does not enter. An optical sensor is provided at the location.

[0020]

According to the first aspect of the present invention, when the diffused light from the diffused light generator enters the light transmitting member, a part of the diffused light is totally reflected on the detection surface. In this case, the critical angle at which total reflection occurs depends on whether moisture is attached to the detection surface. Although the total reflection light on the detection surface is received by the detection unit, the position of the light intensity distribution of the light obtained by the detection unit differs depending on whether moisture is attached to the detection surface or not. Occurs. When the detection unit detects the displacement, the determination unit determines that moisture has adhered to the detection surface.

According to the second aspect of the present invention, when the diffused light from the diffused light generator enters the light transmitting member, a part of the diffused light is totally reflected on the detection surface. In this case, the critical angle at which total reflection occurs depends on the concentration of the solute in the water attached to the detection surface. Although the total reflection light on the detection surface is received by the detection unit, a difference occurs in the displacement amount of the light intensity distribution obtained by the detection unit depending on the concentration of the solute in the water. The determination unit determines the concentration of the solute in the moisture attached to the detection surface according to the position shift amount detected by the detection unit.

According to the third aspect of the present invention, the total reflection light on the detection surface of the light transmitting member is collected by the optical system of the detection unit and forms an image on the position detector.

According to the fourth aspect of the present invention, when the temperature changes, the temperature change is detected by the temperature detecting means.

In the moisture detecting device according to the fifth aspect, since the light transmitting member has a surface parallel to the detection surface, the totally reflected light on the detection surface is reflected by the parallel surface and reenters the detection surface. .

In the moisture detecting device according to the sixth aspect, since the detecting surface of the light transmitting member is covered with the protective plate having water permeability, the moisture passes through the protective plate and adheres to the detecting surface.

In the moisture detecting device according to the seventh aspect, the moisture passes through the moisture introducing hole of the protection plate, is introduced onto the detection surface, and is diffused on the detection surface.

In the moisture detecting device of the present invention, even if there is snow on the protective plate or the protective plate freezes, the protective plate is heated by the heating element, so that the snow and the freezing melt. Moisture flows on the detection surface.

In the water detecting device according to the ninth aspect, the water enters the gap between the detecting surface of the light transmitting member and the diffusing member, and then diffuses along the gap by capillary action.

[0029] In the moisture detecting device according to the tenth aspect, the moisture is:
The light enters the gap between the detection surface of the light transmitting member and the diffusion member through the water introduction hole of the diffusion member.

In the moisture detecting device according to the eleventh aspect, since the detection surface communicates with the drain, the solute in the water remaining on the detection surface due to evaporation of the water is removed to the drain.

According to the twelfth aspect of the present invention, when the moisture detecting device is installed on a road such as when paving a road, only the outer case is installed at the time of construction, and after the completion of the construction, the diffused light generating section and the light transmitting member are provided. , And the inner case accommodating the detection unit is loaded into the outer case.

According to the thirteenth aspect of the present invention, when the moisture adhering to the detection surface is in the state of snow, the light transmitted through the detection surface is diffusely reflected on the snow surface, and a part of the diffusely reflected light is light. Detected by sensor.

[0033]

FIG. 1 shows an example of use of a moisture detector 1 according to one embodiment of the present invention. In the illustrated example of the moisture detecting device 1, a housing case 3 is buried in an installation hole 2 provided on a road surface R, and an apparatus main body 4 is incorporated in the housing case 3. A protective plate 5 having a large number of water passage holes 6 is covered on the upper surface opening of the housing case 3. The protection plate 5 is exposed on the road surface R.

The apparatus main body 4 includes a prism 7 as a light transmitting member, an electroluminescence (hereinafter, referred to as “EL”) 9 constituting a diffused light generator, a detection system including an optical system 11 and a position detector 12. And the unit 10. A code line (not shown) is connected to the EL 9 and the position detector 12, and the code line is drawn out and electrically connected to a power source and a signal processing unit described later.

A support wall 14 protrudes from the inner wall of the casing case 3. A space above the support wall 14 is defined as a water detecting section 2A, and a space below the support wall 14 is defined as a mechanism housing section 2B. The device main body 4 is incorporated in the mechanism housing portion 2B. The prism 7 is held by the support wall 14 so that the detection surface 15 faces upward. In order to prevent the inside of the mechanism housing portion 2B from being flooded, it is desirable to seal the inner edge of the support wall 14.

The protection plate 5 is provided on the detection surface 15 of the prism 7.
Protects it from being damaged. The water accumulated on the road surface R enters the water detection section 2A through the water passage hole 6 and adheres to the detection surface 15 of the prism 7. The water passage hole 6 prevents rocks on the road surface R from passing through as much as possible and prevents clogging with mud.
The optimal hole diameter is set.

It should be noted that the moisture detecting device 1 may be used by being buried in the road surface R as in this embodiment, or may be used by being mounted at an appropriate position on the vehicle 17 as shown in FIG. In the illustrated example, the moisture detector 1 is installed vertically near the wheel 18 in order to introduce the moisture on the road surface R scattered by the rotation of the wheel 18 into the water detecting unit 2A. As long as the water can be introduced into the water detecting section 2A, it may be installed in another portion.

As shown in FIG. 2, the prism 7 is in the form of a triangular prism having a right-angled portion 20. The surface facing the right-angled portion 20 is a detection surface 15, and one surface sandwiching the right-angled portion 20 is diffused. The light incident surface 21 and the other surface are referred to as a totally reflected light emission surface 22. The EL 9 is disposed at a position facing the entrance surface 21 of the prism 7, and the optical system 11 of the detection unit 10 is disposed at a position facing the exit surface 22. EL9 is
Diffuse light having various angle components is generated. This diffused light is applied to the detection surface 15 within the prism 7 by 0%.
It enters at an angle of up to 90 degrees.

It should be noted that the diffused light generator is replaced with the EL9,
As shown in FIG. 16, a light source 24 having a plurality of light emitting diodes 23 arranged thereon and a diffusion plate 25 for diffusing light from each light emitting diode 23 to generate diffused light may be used. In addition, as shown in FIG. 17, if the entrance surface 21 of the prism 7 is formed with a rough surface, the diffusion plate 25 in the embodiment of FIG. 16 can be omitted.

The detection surface 15 of the prism 7 constitutes a total reflection surface for totally reflecting a part of the diffused light inside the prism 7. As for the light totally reflected by the total reflection surface, if the refractive index of the prism 7 is n1 and the refractive index of the substance (air or moisture) on the detection surface 15 is n2 (where n1> n2), the criticality for causing total reflection is obtained. The angle α is given by the following equation.

[0041]

(Equation 1)

Of the diffused light incident on the detection surface 15,
Light having an angle component whose incident angle β is equal to or larger than the critical angle α is totally reflected by the detection surface 15, but light having an angle component equal to or smaller than the critical angle α is detected by the detection surface 1.
5 is transmitted.

The detection unit 10 includes an optical system 11 composed of a collimator lens and a position detector 1 composed of a one-dimensional CCD.
And 2. The optical system 11 is arranged such that, when the substance on the detection surface 15 is a certain concentration of moisture, the light incident at the critical angle α is totally reflected in the lens main plane 1.
1a are arranged so as to be substantially vertical. The position detector 12 is disposed at the focal length f of the optical system 11 so that the optical system 11 and the position detector 12 have a positional relationship such that an image is formed at infinity. As a result, the light incident on the detection surface 15 at the critical angle α or more forms an image on the position detector 12, and an image of the light intensity distribution P as shown in the graph of FIG. 2 is obtained. The boundary position x of the light intensity distribution P in the figure corresponds to the image forming position of the light incident on the detection surface 15 at the critical angle α, and the concentration of the solute in the moisture w attached to the detection surface 15 changes. Then, the refractive index n2 changes, and as a result, the boundary position x shifts.

Now, assuming that the concentration m of the solute in the water w attached to the detection surface 15 changes from m1 to m2 (where m2> m1), the refractive index n2 is changed from n21 to n22.
(Where n22> n21), and therefore
Since the critical angle α increases from α1 to α2 (here, α2> α1), as shown in FIGS. 3 and 4, the boundary position x of the light intensity distribution P on the position detector 12 is shifted from x1 to x2. Shift. In FIG. 3, L1 is the detection surface 1
5 is a path of light incident at a critical angle α1 with respect to L5.
Is a path of light incident on the detection surface 15 at the critical angle α2.

The above specific example is based on the assumption that the moisture w adheres to almost the entire surface of the detection surface 15, but as shown in FIG. Means that water w and air a having different refractive indices coexist on the detection surface 15. In this case, the position detector 12 includes
As shown in FIG. 6, a light intensity distribution P in which the light intensity distribution Pw of the total reflection light on the surface in contact with the moisture w and the light intensity distribution Pa of the total reflection light on the surface in contact with the air a are obtained, The boundary position xa of one light intensity distribution Pw and the other light intensity distribution Pa
Appears at the boundary position xw. In this case, since the boundary position xa for the air a is uniquely determined by the design value, the other boundary position xw is set as the detection value. In FIG. 5, Lw is a path of light incident on the surface in contact with the moisture w at the critical angle αw for the moisture w, and La is air a
Is the path of light that has entered the portion in contact with at a critical angle αa for air a. As is apparent from this specific example, even if the detection surface 15 is not completely filled with the moisture w, the presence or absence of the moisture w on the detection surface 15 and the detection surface 15
It is possible to detect the concentration of the solute in the water w attached to the substrate.

FIG. 7 shows a state in which about one drop of water w has adhered to the detection surface 15, and FIG. 8 shows a state in which about several drops of water w have adhered to the detection surface 15. 7 and 8, L is a path of light incident on the detection surface 15 at a critical angle αw with respect to the moisture w, and the light is totally reflected on the detection surface 15 around the critical angle αw. , Through the detection surface 15. As is clear from FIGS. 7 and 8, the larger the contact area of the moisture w with the detection surface 15, in other words, the larger the amount of the moisture w attached to the detection surface 15, the smaller the amount of light transmitted through the detection surface 15. Increase, but regardless of this,
It is possible to detect the presence / absence of moisture w on the detection surface 15 and the concentration of the solute in the moisture w attached to the detection surface 15.

FIG. 9 shows the light intensity distribution P1 when the amount of water w attached to the detection surface 15 is small (in the case of the specific example of FIG. 7).
And when the amount of adhesion of the moisture w to the detection surface 15 is large (FIG. 8).
(In the case of the specific example (2)), the light intensity distribution P2 is shown. As is clear from the figure, each of the light intensity distributions P1 and P2 has a step h.
Although there is a size difference between the sizes of h1 and h2, the boundary position xw is the same, and about one drop of water w is detected on the detection surface 15 without being affected by the amount of the water w attached to the detection surface 15. Just by adhering, the presence / absence of water w on the detection surface 15 and the concentration of the solute in the water w adhering to the detection surface 15 can be detected. Note that the steps h1, h1 in the light intensity distributions P1, P2
h2 increases in proportion to the amount of moisture w attached to the detection surface 15.

FIGS. 10 and 11 show the principle of detecting the concentration of the solute in the water w. In FIG. 10, Lw0 is the detection surface 15 when the moisture w attached to the detection surface 15 is pure water.
In contrast, Lw1 is a path of light incident at a critical angle αw0 with respect to pure water, and Lw1 is directed to the detection surface 15 when moisture w attached to the detection surface 15 contains a substance such as salt. It is a path of light incident at a critical angle αw1 for water having a concentration. The critical angle αw0 for pure water is uniquely obtained, and the critical angle αw0 for pure water is
The boundary position of the light intensity distribution P generated by the light incident on the position detector 12 at x0 is x0, and the critical angle α for water having a concentration is
Assuming that the boundary position of the light intensity distribution P generated by the light incident on w1 on the position detector 12 is x1, as the concentration of the solute in the water increases, the refractive index of the water w increases and the critical angle αw1 Therefore, the boundary position x1 is displaced leftward with respect to the boundary position x0 for pure water.

FIG. 12 is a specific example of a concentration conversion table for converting the amount of displacement (x1-x0) with respect to the boundary position of pure water into the concentration of a solute in the water w. By preparing such a concentration conversion table in advance and storing it as a table, the concentration of the solute in the water can be easily obtained from the detection result by the position detector 12.

FIG. 13 shows the overall structure of the moisture detecting device 1. The EL 9 as a diffused light generator, the prism 7 as a light transmitting member, the optical system 11 and the position detector 12 are shown.
And a signal processing unit 30 including a microcomputer. The microcomputer of the signal processing unit 30 has a function as a discriminating unit and a function as a light emission control unit. The discriminating unit controls the moisture on the detection surface 15 in accordance with the control flow shown in FIG. The presence or absence of w and the concentration of the solute in the water w are determined.

"ST" in FIG. 14 indicates each step in the control flow. First, in ST1, the discriminating section sets the image data obtained by the position detector 12 composed of a one-dimensional CCD, that is, the 0th data. The light intensity s (0),..., S (Imax) from the pixel to the Imax-th pixel is captured. Here, the 0th pixel is a pixel that exists at a position corresponding to x0.

Next, a difference d (0) between the light intensity s (0) of the 0th (I = 0) pixel and the light intensity s (1) of the 1st (I = 1) pixel is calculated, Hereinafter, similarly, the difference d (I) between the light intensity s (I) of the I-th pixel and the light intensity s (I + 1) of the (I + 1) -th pixel is calculated up to the last Imax-th pixel (ST2). ~ 5).

When the detection of the difference d (I) is completed, ST5
Is determined to be "YES", and in the next ST6, after the boundary position x of the light intensity distribution P to be detected is initialized to zero, it is determined whether or not the difference d (I) is larger than a predetermined threshold value Dth. Is the light intensity s of the (Imax-1) -th pixel.
(Imax-1) and the light intensity s of the Imax-th pixel
The difference d (Imax-1) from (I) is checked sequentially (ST7 to ST10). In the process, the threshold D
If there is d (I) greater than th, the determination in ST8 is “YES”, and the I-th pixel position at this time is x
(ST11), the concentration m of the solute in the water is determined with reference to the above-mentioned concentration conversion table, and this is output (ST12,
13).

In the above embodiment, the prism 7 is a triangular prism having a right angle portion 20.
As shown in FIG. 18, a total reflection surface 40 parallel to the detection surface 15 is provided.
When the prism 7 having a shape having the following shape is used, the light totally reflected on the detection surface 15 is totally reflected on the total reflection surface 40 and is incident on the detection surface 15 again. However, the area of the detection surface 15 can be increased.

In each of the above embodiments, the detection surface 1
5 is made water-repellent, as shown in FIG.
The moisture w attached to the detection surface 15 becomes spherical due to surface tension. As a result, the light transmitted from the prism 7 into the moisture w escapes into the air as it is, and is internally reflected in the moisture w.
It does not enter the prism 7 again. On the contrary,
When the water repellency is not given to the detection surface 15, FIG.
As shown in (2), the moisture w attached to the detection surface 15 may be in the form of a thin film, so that the light transmitted from the prism 7 to the moisture w is internally reflected in the moisture w, and is returned to the prism 7 again.
To enter.

Since the refractive index of the prism 7 and the air and water changes depending on the temperature, the change in the temperature affects the accuracy of the final result of the detection value of the concentration of the solute in the water. Therefore, as shown in FIG. 20, a thermocouple 41 is provided on the surface of the prism 7, a temperature detection signal from the thermocouple 41 is input to a temperature measurement circuit 42 to detect a temperature, and the detected value is used as a signal processing unit. It can also be configured to send to 30.
In this case, the signal processing unit 30 stores a concentration conversion table for each temperature as a table, selects a corresponding temperature concentration conversion table in accordance with the detected temperature value input from the temperature measurement circuit 42, Determine the concentration of the solute in it.

In the embodiment shown in FIG.
Is horizontally supported in the housing case 3, but at the time of implementation, as shown in FIG. 21, for example, the entrance surface 21 is used to prevent the solute from remaining due to spontaneous evaporation of the moisture attached to the detection surface 15. It is desirable to support the prism 7 in a state where the detection surface 15 is appropriately inclined so that the side of the prism 7 becomes lower. In this case, a drain hole 50 communicating with the detection surface 15 is formed in the side wall of the housing case 3, and the drain hole 50 communicates with a drain pipe 51 buried underground. The other configuration in the embodiment of FIG. 21 is the same as that of the embodiment of FIG. 1, and the corresponding components are denoted by the same reference numerals and description thereof will be omitted.

When the detection surface 15 of the prism 7 is in a horizontal state, when the water w attached to the detection surface 15 evaporates naturally, the solute in the water w remains on the detection surface 15, and the remaining solute is detected. As a result, the concentration of the solute in the water w gradually increases. Therefore, when the prism 7 is supported in a state where the detection surface 15 is inclined as in this embodiment, the water w attached to the detection surface 15 flows downward gradually little by little, and the remaining solute is discharged to the drain hole 50.
Through the drain pipe 51, and the inconvenience that the concentration of the solute in the water w gradually increases due to the remaining solute is eliminated.

FIG. 22 shows the detection accuracy S of the moisture detector 1.
In order to increase the N ratio, the prism 7 inside the casing 3
A plate-like diffusing member 52 for diffusing the water w on the detection surface 15 is disposed in parallel with the detection surface 15 in a state close to the detection surface 15. In order to prevent Fresnel reflection of transmitted light from the prism 7, it is preferable that the diffusion member 52 be made of a material having no gloss and easily absorbing light and having a blackish color tone with a surface reflectance as small as possible. desirable. The other configuration is shown in FIG.
This embodiment is the same as the embodiment of FIG. 1, and the same reference numerals as those in the embodiment of FIG.

As shown in FIG. 23, when the amount of water w attached to the detecting surface 15 of the prism 7 is small,
Since the contact area S with No. 5 is small, as shown in FIG.
The above-mentioned step in the light intensity distribution P becomes small. As a result, when there is a variation in sensitivity among the pixels of the position detector 12, the light intensity distribution P does not become a linear ideal state (a state shown by a thick line), but a state containing noise N (a thin line). State), an error occurs in the detection of the boundary position x, and the detection accuracy decreases.

On the other hand, when the diffusing member 52 is disposed close to the detecting surface 15 as in this embodiment, as shown in FIG. 25, the moisture w is generated between the detecting surface 15 of the prism 7 and the diffusing member 52. After entering the gap, it diffuses along the gap by capillary action. As a result, the detection surface 15 of the moisture w
26, the contact area of the light intensity distribution P becomes large, and the step in the light intensity distribution P becomes large as shown in FIG. As a result, even if the light intensity distribution P is in a state including noise N (a state shown by a thin line) due to a variation in sensitivity between pixels of the position detector 12, the boundary position x can be accurately and reliably determined. Detection is possible, and detection accuracy is improved. In FIGS. 23 and 25, arrows indicate the paths of light incident on the detection surface 15.

FIGS. 27 and 28 show another embodiment of the diffusion member 52 described above. The diffusion member 52 in the illustrated example is formed by forming a plurality of moisture introduction holes 53 for introducing moisture w into the detection surface 15 of the prism 7. Each moisture introduction hole 53
Are formed in an upwardly expanding tapered shape. This diffusion member 5
The water w that has flowed down onto the upper surface of No. 2, as shown in FIG.
After being introduced into the gap between the lower surface of the diffusion member 52 and the detection surface 15 of the prism 7 through the water introduction hole 53, it is diffused along the gap onto the detection surface 15 by capillary action.

In this embodiment, a diffusion member 52 is provided separately from the above-mentioned protection plate 5. However, as in the embodiment shown in FIG. 30, the protection plate 5 has the function of the diffusion member 52. For example, the diffusion member 52 can be omitted. In the embodiment of FIG. 30, a plurality of moisture introduction holes 53 are formed in the protective plate 5, and the protective plate 5 and the prism 7 are arranged so that the protective plate 5 and the detection surface 15 of the prism 7 are close to each other. Is done.
According to this embodiment, after the moisture w is introduced into the gap between the lower surface of the protective plate 5 and the sensing surface 15 of the prism 7 through the moisture introduction hole 53, the sensing surface 1 is formed along the gap by capillary action.
5 is diffused.

FIG. 31 shows a structure in which a heating element 55 is provided inside the casing case 3 for heating the protection plate 5. The heating element 55 is formed of a heating wire such as a nichrome wire, and the heating element 55 is disposed below the protection plate 5 and close to the protection plate 5. This heating element 55
The power is supplied to the heater circuit 56 housed in the housing case 3. According to this embodiment, the protective plate 5
Even if snow falls on the protective plate 5 or the protective plate 5 freezes, the heating element 55 is energized to perform a heating operation, thereby melting snow and ice and allowing the water w to pass through the protective plate 5 and adhere to the detection surface 15. Can be done. Although this embodiment is configured by adding a heating element 55 to the embodiment of FIG. 22, similar heating elements 55 can be provided in appropriate places in other embodiments.

FIG. 32 shows another embodiment of the housing case 3. The illustrated case 3 has a double structure.
It comprises an outer case 3a having an upper surface opening buried inside the installation hole 2 provided on the road surface R, and an inner case 3b fitted into the inner hole 57 of the outer case 3a and fixed with bolts 58. The inner case 3b is detachable with respect to the outer case 3a. Inside the inner case 3b, a prism 7 as a light transmitting member, an EL 9 constituting a diffused light generator, an optical system 11, and a position detector 12 are provided. The apparatus main body 4 including the detecting unit 10 is provided. In the upper surface opening of the inner case 3b,
A protection plate 5 having a large number of water holes 6 is covered.

The inner surface of the bottom of the outer case 3a and the inner case 3b
Connectors 60 and 61 that can be mechanically and electrically coupled are provided on the outer surface of the bottom of the connector. Inner case 3b
The EL 9 and the position detector 12 are electrically connected to the connector 61 of FIG. A cord line 62 drawn out is connected to the connector 60 of the outer case 3a. The code line 62 is connected to a power supply and a signal processing unit.

The moisture detecting apparatus 1 of this embodiment is designed in consideration of being installed when pavement or repair of a road is performed. When the pavement or repair of a road is performed, heat and smoothness of asphalt are reduced. In this case, an installation method is adopted in which the apparatus main body 4 is not damaged by heat or impact even if pressure for the operation is applied. FIG. 33 shows an installation method of the moisture detecting device 1 of this embodiment. First, a device in which a dummy object 3c instead of the inner case 3b is loaded in the inner hole 57 of the outer case 3a is buried in the spread asphalt. I do. When the paving work is completed, the dummy object 3c is extracted from the outer case 3a after waiting for the temperature to drop, and then the inner case 3b in which the apparatus main body 4 is incorporated is inserted into the inner hole 57 of the outer case 3a. Fix it.

FIG. 34 shows an arrangement in which an optical sensor 70 such as a photodiode is provided at a position where regular reflection light from the detection surface 15 of the prism 7 does not enter, specifically, at the entrance surface 21 side. . The optical sensor 70 is for receiving diffusely reflected light from the adhered substance adhered to the detection surface 15 of the prism 7. When the optical sensor 70 receives the diffusely reflected light, the adhered substance on the detection surface 15 is When it is determined that it is in a snow state and the optical sensor 70 does not receive the diffuse reflection light, it is determined that the attached matter on the detection surface 15 is in a water state.

FIG. 34 shows the path of the incident light L when the attached matter w1 in the state of water adheres to the detection surface 15. Of the incident light L having an incident angle of 0 to 90 degrees, the incident light L is larger than the critical angle. Is regularly reflected by the detection surface 15, and light smaller than the critical angle is detected by the detection surface 1.
5 and the deposit w1. Therefore, the optical sensor 7
0 does not receive diffuse reflection light. FIG. 35A shows the incident light L when the attached matter w2 in a snow state adheres to the detection surface 15.
35, light having a critical angle or more is specularly reflected by the detection surface 15, but light having a smaller angle than the critical angle is transmitted through the detection surface 15, and the transmitted light is shown in the enlarged view of FIG. Thus, the light is diffusely reflected on the surface of the attached matter w2. As a result, the diffuse reflection light (indicated by a thin arrow in the figure) returns to the detection surface 15 within a range of 0 to 180 degrees, and a part thereof is
And is received by the optical sensor 70.

FIG. 36 shows a specific example of the moisture detecting device 1 configured by combining the configurations of the above embodiments. The embodiment shown in the figure is the outer case 3 used in the embodiment shown in FIG.
a and an inner case 3b, a protective case 5 having a water introduction hole 53 having a diffusion function used in the embodiment of FIG. 30, and a thermocouple used in the embodiment of FIG. The thermometer includes the thermometer 41, the heating element 55 used in the embodiment of FIG. 31, and the like.

In this specific example, due to the installation space, a heating element 55 is provided at the bottom of the inner case 3b, and the heat of the heating element 55 is transmitted to the protective plate 5 via the inner case 3b. I have. The outer case 3a and the inner case 3b have drain holes 50a, 50b communicating with each other.
The drain hole 50a of the outer case 3a is communicated with a drain pipe 51 buried underground. A code line 72 for electrically connecting an internal circuit unit 71 such as a heater circuit to an external power supply or signal processing unit is inserted through the drain pipe 51. Further, in this specific example, the inner case 3
A drying agent 73 such as silica gel is loaded in the inside b to absorb the moisture in the inner case 3b.

[0072]

According to the first aspect of the present invention, the critical angle at which total reflection occurs depends on whether or not moisture has adhered to the detection surface of the light transmitting member, and the total reflection light on the detection surface is detected by the detection unit. Since light is received and the displacement of the light intensity distribution due to the attachment of moisture to the detection surface is detected to determine the attachment of moisture to the detection surface, even if only one drop of moisture adheres to the detection surface, Adhesion of moisture can be reliably detected.

According to the second aspect of the present invention, the displacement of the light intensity distribution due to the attachment of moisture to the detection surface is detected, and the concentration of the solute in the moisture attached to the detection surface is determined according to the displacement amount. Therefore, the concentration of the solute in the water can be detected reliably and accurately regardless of the amount of the water adhering to the detection surface.

According to the third aspect of the present invention, since the optical system and the position detector are arranged so as to form an image at infinity and the detection unit is formed, the positional deviation of the light intensity distribution due to the adhesion of moisture to the detection surface is reduced. It can be detected reliably.

According to the fourth aspect of the present invention, since the temperature detecting means for detecting the temperature is provided in the light transmitting member, it is possible to detect the temperature change with high accuracy.

According to the fifth aspect of the present invention, since the light transmitting member is provided with a surface parallel to the detection surface, the area of the detection surface can be increased even if the light from the diffused light generator is the same.

According to the sixth aspect of the present invention, since the detection surface of the light transmitting member is covered with the water-resistant protective plate, it is possible to prevent the detection surface from being damaged and to suppress a decrease in detection accuracy.

According to the seventh aspect of the present invention, since the protective plate having the water introduction hole is disposed close to the detection surface so as to diffuse the water on the detection surface, the SN ratio of the detection accuracy can be increased.

According to the eighth aspect of the present invention, since the protective plate is heated by the heating element, the snow and freezing of the protective plate can be melted, and moisture can be attached to the detection surface.

According to the ninth aspect of the present invention, since the diffusion member for diffusing moisture on the detection surface is provided at a position close to the detection surface of the light transmitting member, the SN ratio of detection accuracy can be increased.

According to the tenth aspect of the present invention, since a plurality of moisture introduction holes for introducing moisture onto the detection surface are opened in the diffusion member, moisture can be reliably introduced onto the detection surface.

According to the eleventh aspect of the present invention, since the detection surface of the light transmitting member is communicated with the drainage portion, the water adhering to the detection surface naturally evaporates and the remaining solute can be removed to the drainage hole.

According to the twelfth aspect of the present invention, the diffused light generating section, the light transmitting member, and the detecting section are housed and arranged inside the inner case of the housing case having a double structure, and the inner case is moved to the outer case after installation work. Since it can be set, even if the moisture detection device is installed during pavement on the road, it will not be damaged by heat or pressure.

According to the thirteenth aspect of the present invention, since the optical sensor is provided at a position where the specularly reflected light from the detection surface does not enter, whether the substance adhering to the detection surface is in a water state or a snow state is determined. I can judge.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a state in which a moisture detecting device according to an embodiment of the present invention is installed on a road surface.

FIG. 2 is an explanatory diagram showing a configuration and a principle of a moisture detection device.

FIG. 3 is an explanatory diagram showing the path of total reflection light when the concentration of a solute in moisture adhering to a detection surface is different.

FIG. 4 is an explanatory diagram showing a displacement of a light intensity distribution in the example of FIG. 3;

FIG. 5 is an explanatory diagram showing a path of totally reflected light when moisture adheres to a part of the detection surface.

FIG. 6 is an explanatory diagram showing a position shift of a light intensity distribution in the example of FIG. 5;

FIG. 7 is an explanatory diagram showing a light path when about one drop of moisture adheres to a detection surface.

FIG. 8 is an explanatory diagram showing a light path when about several drops of water adhere to the detection surface.

FIG. 9 is an explanatory diagram showing a light intensity distribution in the example of FIGS. 7 and 8;

FIG. 10 is an explanatory diagram showing a path of total reflection light in a case where moisture adhering to a detection surface has pure water and a case where moisture has a concentration.

FIG. 11 is an explanatory diagram showing a position shift of a light intensity distribution in the example of FIG. 10;

FIG. 12 is an explanatory diagram showing a specific example of a concentration conversion table.

FIG. 13 is a block diagram showing the overall configuration of the moisture detection device.

FIG. 14 is a flowchart illustrating a flow of control by a determination unit.

FIG. 15 is an explanatory diagram showing a state in which the moisture detection device is attached to a vehicle.

FIG. 16 is an explanatory diagram showing another embodiment of the diffused light generator.

FIG. 17 is an explanatory view showing another embodiment of the diffused light generator.

FIG. 18 is an explanatory view showing another embodiment of the prism.

FIG. 19 is an explanatory diagram showing light paths on a detection surface having water repellency and a detection surface having no water repellency.

FIG. 20 is a block diagram of an embodiment in which a prism is provided with temperature detecting means.

FIG. 21 is a sectional view showing an embodiment in which a prism is supported in a state where a detection surface is inclined.

FIG. 22 is a sectional view showing an embodiment in which a diffusion member is used.

FIG. 23 is an explanatory diagram showing a light path when a small amount of water adheres to the detection surface.

FIG. 24 is an explanatory diagram showing a light intensity distribution in the example shown in FIG. 23;

FIG. 25 is an explanatory diagram showing a state of moisture and a light path when a diffusion member is used.

26 is an explanatory diagram showing a light intensity distribution in the example shown in FIG. 25.

FIG. 27 is a cross-sectional view of a diffusion member having a water introduction hole.

FIG. 28 is a plan view of a diffusion member having a water introduction hole.

FIG. 29 is a cross-sectional view for explaining a process of diffusing moisture on the detection surface.

FIG. 30 is a sectional view showing an embodiment in which a protective plate having a diffusion function is used.

FIG. 31 is a cross-sectional view showing an embodiment using a heating element.

FIG. 32 is a cross-sectional view showing an embodiment in which a housing case having a double structure is used.

FIG. 33 is a sectional view showing a method of installing the embodiment of FIG. 32;

FIG. 34 is an explanatory diagram showing a configuration of an embodiment using an optical sensor and a light path when a substance in a water state adheres to a detection surface.

FIG. 35 is an explanatory diagram showing a light path when a snowy substance adheres to the detection surface.

FIG. 36 is a cross-sectional view showing a specific example configured by combining the configurations of the embodiments.

FIG. 37 is a cross-sectional view showing the configuration and principle of a conventional moisture detection device.

FIG. 38 is a plan view showing a problem of the conventional example when the space between electrodes is not filled with water.

FIG. 39 is a cross-sectional view showing a problem of the conventional example when the water level on the road surface is not sufficient.

FIG. 40 is a plan view showing a problem of a conventional example in a case where current is applied only partially between electrodes.

[Explanation of symbols]

 REFERENCE SIGNS LIST 5 protective plate 6 water hole 7 prism 9 EL 10 detection unit 11 optical system 12 position detector 15 detection surface 30 signal processing unit 41 thermocouple 42 temperature measurement circuit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yuichi Niimoto F-term in Omron Co., Ltd. 10-10 Hanazono Dodocho, Ukyo-ku, Kyoto-shi, Kyoto 2G059 AA01 AA05 BB04 CC02 CC09 CC20 DD12 DD13 DD16 EE02 FF03 GG02 JJ11 JJ12 KK04 LL01 MM01 MM09

Claims (13)

[Claims] A diffused light generating section and a detecting surface on which a part of the diffused light from the diffused light generating section is totally reflected, and a difference in critical angle occurs depending on whether or not moisture adheres to the detecting surface. A light transmitting member, a detecting unit that receives total reflection light on the detection surface of the light transmitting member, and detects a position shift of a light intensity distribution due to adhesion of moisture to the detecting surface, and the detecting unit detects the position shift. A moisture detecting device comprising: a determination unit configured to determine adhesion of moisture to a detection surface based on detection of a shift. A diffused light generating section, and a detecting surface on which a part of the diffused light from the diffused light generating section is totally reflected, wherein a critical angle differs depending on a concentration of a solute in water adhering to the detecting surface. A light-transmitting member that causes the light-transmitting member, a detector that receives total reflection light on the detection surface of the light-transmitting member, and detects a position shift of a light intensity distribution due to adhesion of moisture to the detection surface. A determination unit configured to determine a concentration of a solute in water attached to the detection surface in accordance with the detected positional shift amount. 3. The moisture detection device according to claim 1, wherein the detection unit includes an optical system arranged to form an image at infinity and a position detector. 4. The moisture detecting device according to claim 1, wherein the light transmitting member is provided with temperature detecting means for detecting a temperature. 5. The moisture detecting device according to claim 1, wherein the light transmitting member has a surface parallel to the detecting surface. 6. The moisture detecting device according to claim 1, wherein the detecting surface of the light transmitting member is covered with a water-permeable protective plate. 7. The moisture detecting device according to claim 1, wherein the sensing surface of the light transmitting member has a plurality of moisture introducing holes for introducing moisture onto the sensing surface. A moisture detection device which is covered with a plate, and wherein the protection plate is provided close to the detection surface so as to diffuse moisture on the detection surface. 8. The moisture detecting device according to claim 6, wherein the protective plate is heated by a heating element. 9. The moisture detecting device according to claim 1, wherein a diffusion member for diffusing moisture on the detection surface is provided at a position close to the detection surface of the light transmitting member. Moisture detector. 10. The moisture detecting device according to claim 1, wherein a diffusion member for diffusing moisture attached to the detection surface is provided at a position near the detection surface of the light transmitting member. A moisture detecting device, wherein the diffusion member has a plurality of moisture introducing holes for introducing moisture onto the detection surface. 11. The moisture detecting device according to claim 1, wherein the detecting surface of the light transmitting member communicates with a drain for draining moisture on the detecting surface. Detection device. 12. The moisture detecting device according to claim 1, wherein the diffused light generating section, the light transmitting member, and the detecting section are formed in a double case of an inner case of a housing case. A moisture detection device housed and disposed inside, wherein the inner case is detachably formed with respect to an outer case. 13. The moisture detecting device according to claim 1, wherein an optical sensor is provided at a position around the light transmitting member where regular reflection light from a detection surface is not incident. Moisture detector.